Question

My machine is on PDT and if I say DateTime.Now, then I will get a local time which is say equivalent to Sep-18th 2012 6:00:00 AM. I want to get UTC equivalent for this datetime instance. UTC time will be 7 hours ahead Of PDT and 8 hours ahead of PST. I want to consider daylight saving automatically.

Any idea on how I can do this?

Answer 1

You can use

var now = DateTime.UtcNow;

To convert an existing DateTime, assuming it has time zone information, you can use DateTime.ToUniversalTime(). If you get the DateTime instance using e.g.

var localNow = DateTime.Now;  // Has timezone info

it will have time zone information. If you create it e.g. using a tick count, it will not contain timezone information unless you explicitly supply it.

var unspecifiedNow = new DateTime(someTickCount); // No timezone info

It is worth mentioning that timezone handling in .NET is not optimal.  You may wish to have a look at Noda Time (a project by Jon Skeet) if you need to do anything elaborate involving time zones.